Medicine:Radial neuropathy

Short description: Human disease

Radial neuropathy
Other names	Radial mononeuropathy, Saturday night palsy
The suprascapular, axillary, and radial nerves.
Symptoms	Wrist drop
Causes	Broken bone, Direct nerve injury
Diagnostic method	MRI, Ultrasound
Treatment	Corticosteroid, Pain medication

Radial neuropathy is a type of mononeuropathy which results from acute trauma to the radial nerve that extends the length of the arm. It is known as transient paresthesia when sensation is temporarily abnormal.

Signs and symptoms

Symptoms of radial neuropathy vary depending on the severity of the trauma; however, common symptoms may include wrist drop, numbness on the back of the hand and wrist, and inability to voluntarily straighten the fingers. Loss of wrist extension is due to loss of the ability to move of the posterior compartment of forearm muscles. In the event of lacerations to the wrist area the symptom would therefore be sensory. Additionally, depending on the type of trauma, other nerves may be affected such as the median nerve and axillary nerves.

Causes

File:Radial Nerve - Anatomy, Innervation & Distribution - Human Anatomy Kenhub 1.webm

Humerus - anterior view

There are many ways to acquire radial nerve neuropathy, including:

• Upper arm - a fracture of the bone
• Elbow - entrapment of the nerve
• Wrist - elbow deformity and soft-tissue masses
• Axilla - here the most common cause is compression. However, a dislocation of the humerus is a possible factor as well. It could also be due to brachial plexus compression.

Mechanism

The mechanism of radial neuropathy is such that it can cause focal demyelination and axonal degeneration. These would be caused via laceration or compression of the nerve in question.

Diagnosis

Radial neuropathy may be diagnosed using MRI, ultrasound, nerve conduction study or electromyography (EMG).

Treatment

Hand tendons

The treatment and management of radial neuropathy can be achieved via the following methods:

• Physical therapy or occupational therapy
• Surgery (depending on the specific area and extent of damage)

• Tendon transfer (the origin remains the same but insertion is moved)

• Splinting

Prognosis

Radial neuropathy is not necessarily permanent, though there could be partial loss of movement or sensation. Complications include deformity of the hand in some individuals. If the injury is axonal (the underlying nerve fiber itself is damaged), recovery may take months or years and full recovery may never occur. EMG and nerve conduction studies are typically performed to diagnose the extent and distribution of the damage, and to help with prognosis for recovery.

Culture and society

There are a number of terms used to describe radial nerve injuries, which are dependent on the causation factor such as:

• Honeymoon palsy from another individual sleeping on and compressing one's arm overnight.
• Saturday night palsy from falling asleep with one's arm hanging over the arm rest of a chair, compressing the radial nerve.
• Saturnine palsy from lead poisoning
• Squash palsy, from traction forces associated with the sport squash, happens to squash players during periods between matches.

See also

• Crutch paralysis
• Peripheral neuropathy

Further reading

• Cartwright, Michael S.; Yoon, Joon Shik; Lee, Kyu Ho; Deal, Nicole; Walker, Francis O. (1 April 2011). "Diagnostic Ultrasound for Traumatic Radial Neuropathy". American Journal of Physical Medicine & Rehabilitation 90 (4): 342–343. doi:10.1097/PHM.0b013e3181e29daa. ISSN 0894-9115. PMID 20531154. 
• Tuncel, Umut; Turan, Aydin; Kostakoglu, Naci (1 January 2011). "Acute closed radial nerve injury". Asian Journal of Neurosurgery 6 (2): 106–109. doi:10.4103/1793-5482.92175. ISSN 1793-5482. PMID 22347334. 

External links

Classification	D ICD-10: G56.3 ICD-9-CM: 354.3 MeSH: D020425
External resources	eMedicine: neuro/587